Dear amber users
Recently we downloaded the latest version of the 3ob set for use used it to
run calculations at DFTB level with a Mg atom in the QM region, in order to
compare the previously obtained results using AM1/d. We tried different
starting geometries and 2 different proteins, but in all cases the result
is the same, we have a problem in the convergence, related with the
Eigenvalue solver of the form:
QMMM SCC-DFTB: ***************************************************
QMMM SCC-DFTB: ERROR ON EWEVGE (Eigenvalue solver).
QMMM SCC-DFTB: ewevge: ier = 307 inner_scf_count= 1
QMMM SCC-DFTB: ***************************************************
QMMM SCC-DFTB: !!!! ============= WARNING ============= !!!!
QMMM SCC-DFTB: Convergence could not be achieved in this step.
QMMM SCC-DFTB: The calculation will continue, but energies and
QMMM SCC-DFTB: forces for this step will not be accurate.
After a search in the list, we came with a few options that we discarded.
Some pointed to a problem in the system, other told to change the
dftb_telec flag. The later was to no use, the former does not seem to be a
the problem with the structure. Either way, all the search results, were
older than the new data set 3ob-3-1 released.
As well, other processes with the a QM region with only H, C, N and O atoms
seem to be running OK. When I take of the QM region the Mg and the ATP, the
calculations run without that problem, but with either of them shows the
same problem. It seems that something happen when it has to use the slk
files for the P or the Mg atom.
Thanks for your kind attention
Best Wishes
Dr. Emilio Lence Quintana
Organic Chemistry Department-CIQUS
Univesity of Santiago de Compostela
15782 Santiago de Compostela, Spain
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Received on Thu Oct 01 2015 - 06:00:03 PDT
